Modeling the Covariance Matrix for the Power Spectra Before and After the BAO Reconstruction  

作　　者：Ruiyang Zhao Kazuya Koyama Yuting Wang Gong-Bo Zhao 

机构地区：[1]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [2]School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China [3]Institute of Cosmology&Gravitation,University of Portsmouth,Dennis Sciama Building,Portsmouth,PO13FX,UK [4]Institute for Frontiers in Astronomy and Astrophysics,Beijing Normal University,Beijing 102206,China [5]Chinese Academy of Sciences South America Center for Astronomy(CASSACA),National Astronomical Observatories of China,Beijing 100101,China

出　　处：《Research in Astronomy and Astrophysics》2024年第12期156-174,共19页天文和天体物理学研究(英文版)

基　　金：supported by National Key R&D Program of China No.2023YFA1607803;National Natural Science Foundation of China (NSFC,grant No.11925303);by the CAS Project for Young Scientists in Basic Research (No.YSBR-092);supported by the Chinese Scholarship Council (CSC) and the University of Portsmouth;supported by the STFC grant ST/W001225/1.Y.W.;supported by National Natural Science Foundation of China (NSFC,grant Nos.12273048 and 12422301);by National Key R&D Program of China No.2022YFF0503404;by the Youth Innovation Promotion Association CAS;by the Nebula Talents Program of NAOC.G.B.Z.;supported by science research grants from the China Manned Space Project with No.CMS-CSST-2021-B01;the New Cornerstone Science Foundation through the XPLORER prize;supported by the ICG,SEPNet and the University of Portsmouth。

摘　　要：The baryon acoustic oscillations (BAO) reconstruction plays a crucial role in cosmological analysis for spectroscopic galaxy surveys because it can make the density field effectively more linear and more Gaussian.The combination of the power spectra before and after the BAO reconstruction helps break degeneracies among parameters,then improves the constraints on cosmological parameters.It is therefore important to estimate the covariance matrix between pre-and post-reconstructed power spectra.In this work,we use perturbation theory to estimate the covariance matrix of the related power spectra multipoles,and check the accuracy of the derived covariance model using a large suite of dark matter halo catalogs at z=0.5.We find that the diagonal part of the auto covariance is well described by the Gaussian prediction,while the cross covariance deviates from the Gaussian prediction quickly when k>0.1 h Mpc^(-1).Additionally,we find the non-Gaussian effect in the nondiagonal part of the cross covariance is comparable to,or even stronger than,the pre-reconstruction covariance.By adding the non-Gaussian contribution,we obtain good agreement between analytical and numerical covariance matrices in the non-diagonal part up to k■0.15 h Mpc^(-1).The agreement in the diagonal part is also improved,bu still under-predicts the correlation in the cross covariance block.

关 键 词：(cosmology) large-scale structure of universe-cosmology theory-(cosmology) cosmological parameters 

分 类 号：P144.1[天文地球—天体物理]